female dog aggressive on leash or in harness

Question
I have two wonderful dogs, a 10yr old male border collie/husky
and 6yr old female siberian husky.  Both are calm and
gentle around all people, and even cats. HOWEVER, I am having
an increasingly difficult time with them under certain situations.
The female, who has a dominant personality, becomes
aggressive when passing other dogs while on leash or in harness
(I have been skijoring, both on skis and roller blades). This
causes difficulties in parks and trails where there are always lots
of other dogs. She also becomes aggressive when in a familiar
territory where there is new dog present, particularly another
female. When the female becomes aggressive, the male follows
her lead. We have started bringing them to a "doggie day care"
for supervised play every once in a while so they can be
socialized with other dogs  They do great in that setting and
have never caused any problems; in fact, we are always being
complimented on their good behavior with other dogs. I have
also not had a problem with them in dog parks. Unfortunately, if
you put them on a leash or in harness all of those good manners
get completely forgotten, which makes them very difficult to
handle if I'm wearing roller blades! Any thoughts on what's
going on here? What is the best way to handle this behavior?

Thanks for your insight!

Answer
Dear Laura,
I too have a dog who behaves like this and I must say it is a very trying habit to break. When a dog is on a leash it sees its personal space as being invaded easier by others, humans as well as other animals and is more prone to react aggerssively to intrusion. Also what is happening in selective situations is, your Husky who is the dominant one is protecting the other dog which she sees as her dog. All you can do is what you have been doing and show her clearly how much you dissapprove of her actions when she behaves this way by stern reprimand. Unfortunately with my dog at times it has been neccessary to just try to go places that are a bit quieter, so I might have less trouble to begin with.
I hope this helps.
Faye and Husky Crew.